diff --git a/smash/core/simulation/_standardize.py b/smash/core/simulation/_standardize.py
index e71e03ee..441ef1a5 100644
--- a/smash/core/simulation/_standardize.py
+++ b/smash/core/simulation/_standardize.py
@@ -330,7 +330,7 @@ def _standardize_simulation_optimize_options_descriptor(
 def _standardize_simulation_optimize_options_net(
     model: Model, bounds: dict, net: Net | None, **kwargs
 ) -> Net:
-    x, y, nd = model.physio_data.descriptor.shape
+    nrow, ncol, nd = model.physio_data.descriptor.shape
 
     bound_values = list(bounds.values())
     ncv = len(bound_values)
@@ -340,7 +340,7 @@ def _standardize_simulation_optimize_options_net(
         net = Net()
 
         net.add_dense(nd * 3, input_shape=nd, activation="relu")
-        net.add_dense(round(np.sqrt(nd * ncv) * np.log(x * y)), activation="relu")
+        net.add_dense(round(np.sqrt(nd * ncv) * np.log(nrow * ncol)), activation="relu")
         net.add_dense(ncv * 3, activation="relu")
         net.add_dense(ncv, activation="tanh")
         net.add_scale(bound_values)
@@ -350,7 +350,7 @@ def _standardize_simulation_optimize_options_net(
             # % Check input shape
             net_in = net.layers[0].input_shape
 
-            x_in = (x, y, nd) if len(net_in) == 3 else (nd,)  # in case of cnn and mlp resp.
+            x_in = (nrow, ncol, nd) if len(net_in) == 3 else (nd,)  # in case of cnn and mlp resp.
 
             if net_in != x_in:
                 raise ValueError(